Analysis and Isolation of Secondary Metabolites of Bipolarissorokiniana by Different Chromatography Techniques and the Spectrum of Their Biological Activity
Abstract
Secondary metabolites were isolated from cultures of four geographically distant isolates of the cosmopolitan fungus, Bipolaris sorokiniana for intense biological characterization. Analysis of extracts from their liquid and solid cultures with TLC and HPLC-MS showed high similarity of their composition despite on fungal origin. From the extracts of B. sorokiniana 14 metabolites (terpenes, quinones, xanthones etc.) were isolated using column chromatography and preparative HPLC; among them, 12 known substances were identified. Chloromonilinic acid B (CAB) showed the highest level phytotoxic activity on wheat leaves. The most of isolated compounds inhibited growth of Bacillus subtilis, of which methyl-8,3-hydroxy-3-methyl-4-chloroxanthon-1-carboxilate (MMC) demonstrated the strongest activity. Some metabolites of B. sorokiniana (CAB and MMC) were shown to have insecticidal activity against common cereal aphid. All the compounds were cytotoxic (especially, cochlioqionones and fusaroproliferin) when tested on Sf9 cell line. However, no one was acute toxic for infusoria. Evidently, the production of multiple bioactive compounds makes B. sorokiniana a strong competitor in different ecological niches and a dangerous contaminant of grain.